Answer:

Introduction:
Crypts of Lieberkuhn are small tubular glands located in the small intestine. These glands secrete various enzymes, mucus, and other substances that help in digestion and absorption of nutrients. One of the important enzymes secreted by these glands is lysozyme, which has antibacterial properties.

Cell Types in Crypts of Lieberkuhn:
There are several types of cells present in the crypts of Lieberkuhn, including:

1. Argentaffin cells: These cells are responsible for producing hormones such as serotonin, which helps in regulating intestinal motility and secretion.

2. Paneth cells: These cells are specialized secretory cells that secrete lysozyme, phospholipase A2, and other antimicrobial peptides. They are located at the base of the crypts and help in protecting the intestinal epithelium from bacterial invasion.

3. Zymogen cells: These cells secrete digestive enzymes such as amylase, lipase, and protease, which help in digesting carbohydrates, fats, and proteins.

4. Kupffer cells: These cells are present in the liver and are responsible for phagocytosing bacteria and other foreign particles.

Lysozyme Secretion:
Paneth cells are the primary source of lysozyme secretion in the crypts of Lieberkuhn. Lysozyme is an enzyme that breaks down bacterial cell walls by hydrolyzing the peptidoglycan layer. This helps in preventing bacterial invasion and protects the intestinal epithelium from infection.

Conclusion:
In conclusion, the cells that secrete anti-bacterial lysozyme in the crypts of Lieberkuhn are Paneth cells. These cells are located at the base of the crypts and help in protecting the intestinal epithelium from bacterial invasion. Lysozyme is an important enzyme that has antibacterial properties and helps in maintaining the integrity of the intestinal mucosa.

Paneth cells are present in the mucosa between the bases of villi of small intestine (Crypts of Lieberkuhn). The function of these cells is to secrete antibacterial lysozyme.